EP3737897B1

EP3737897B1 - A mobile cooling device

Info

Publication number: EP3737897B1
Application number: EP19700237.1A
Authority: EP
Inventors: Tomas ZUKAS; Liutauras VAITKUS
Original assignee: Carlsen Baltic
Current assignee: Carlsen Baltic
Priority date: 2018-01-12
Filing date: 2019-01-11
Publication date: 2021-12-08
Anticipated expiration: 2039-01-11
Also published as: EP3737897A1; ES2904926T3; WO2019138067A1

Description

The present disclosure relates to mobile cooling devices such as trucks, containers and similar mobile units with cooling capabilities and adapted for transporting food, produce, and like products required to be maintained in cold condition.
A method for the cooling of a chamber of such a mobile cooling device is also the subject of the invention.
Mobile cooling devices are used for the transport of cooled commodities, and with good insulation, a closed cooling chamber consumes only limited cooling power. E.g. in combination with repeated opening and closing of doors, e.g. in connection with local distribution of cooled commodities, cooling capacity and power consumption can, however, become an important issue. Even though lost cooling energy can be furnished by a mechanical cooling assembly, e.g. driven by the main engine of the mobile cooling device, rapid or frequent re-cooling after a cooling chamber has been opened, may be problematic, e.g. due to increased need for defrosting etc.
A mobile cooling device of the prior art is known from US 6467293 B1 . Other similar cooling devices are known from documents US 2008/011013 A1 , US 3359751 A and US 2318532 A .

SUMMARY

To increase cooling capacity, to avoid de-freezing, and to reduce power consumption in refrigerated mobile cooling devices, a mobile cooling device and a method according to the independent claims are provided.
In a first aspect defined by independent claim 1, a mobile cooling device is provided. The cooling device having a freezing chamber, an eutectic cooling system arranged to cool the freezing chamber, a chilling chamber, and a separation wall between the chilling chamber and the freezing chamber, wherein the separation wall comprises a divider plate having a freezing side towards the freezing chamber and a chilling side towards the chilling chamber, and wherein the separation wall forms a closed structure preventing exchange of air between the freezing chamber and the chilling chamber. The separation wall further comprises a freezing duct extending from a freezing inlet to a freezing outlet along the freezing side and a chilling duct extending from a chilling inlet to a chilling outlet along the chilling side.
Due to the separation wall between the freezing chamber and the chilling chamber, the chilling chamber can be cooled by thermal convection through the separation wall. Due to the closed structure of the divider plate, the thermal convection occurs without communication of air between the chilling and freezing chambers and icing of the freezing chamber can therefore be avoided.
Due to the two separate ducts, i.e. the freezing duct and the chilling duct, the ability to control thermal convection through the divider plate is increased, and the ability to obtain a desired temperature in the chilling chamber is increased.
By the term "mobile cooling device" is herein understood any means for transporting goods, e.g. a container, a vehicle such as a truck or a car, a plane, or a ship etc.
The mobile cooling device according to the invention could particularly be a vehicle designed to bring cooled or frozen food products to the consumer. Particularly, the mobile cooling device may be configured for frozen articles in the freezing chamber, e.g. to be kept at temperatures below minus 18 or minus 25, even below minus 33 degrees, and for articles to be kept at refrigerator temperatures in a chilling chamber e.g. at 12, 8, 5 or 2 degrees. The mobile cooling device may have several freezing chambers and several cooling chambers.
The freezing chamber is cooled by a eutectic cooling system which enables a high cooling performance even without supply of energy for cooling purpose. The eutectic cooling system may e.g. comprise a compressor driven cooling system with an evaporator encapsulated in a block of a eutectic material capable of accumulating thermal energy. At least the evaporator and the eutectic material are preferably arranged inside the freezing chamber.
The divider plate has a freezing side towards the freezing chamber and a chilling side towards the chilling chamber. The divider plate may e.g. be a flat plate e.g. made of a blank of a sheet material, e.g. comprising aluminium. Alternatively, the divider plate may comprise surface area increasing structures, e.g. in the shape of fins or similar surface textures for increasing thermal convection through the divider plate.
The mobile cooling device may comprise walls, a ceiling, and a bottom arranged such that they form one large chamber which is divided into the chilling chamber and freezing chamber by the separation wall. The walls, ceiling, and bottom may e.g. be the outer walls of a refrigerated vehicle, container, or the like.
The divider plate may form a structural entity of the chassis of the mobile cooling device and thereby help stiffening or strengthening the device structurally. For that purpose, the divider plate may be permanently sealed to the walls, to the ceiling, and to the bottom.
In one embodiment, the walls, bottom and ceiling are not fixed to the divider plate, but the divider plate is movable in the space to thereby allow shifting between different positions. This allows reconfiguration between different sizes of the freezing chamber relative to the chilling chamber. A resilient gasket between the divider plate and the walls, ceiling and bottom may prevent air-exchange between the freezing and chilling chamber.
In one embodiment, several chilling chambers are cooled by the same freezing chamber, and in another embodiment several freezing chambers are arranged to cool one or more chilling chambers.
In one specific embodiment, a quadrangular or rectangular freezing chamber is located with two chilling chambers on opposite sides, i.e. the freezing chamber is between two chilling chambers, and in another embodiment, two chilling chambers are located against two adjacent sides of the freezing chamber.
The freezing duct extends from a freezing inlet to a freezing outlet along the freezing side. The freezing duct may cover a large part of the freezing side, e.g. more than 50 percent, or more than 60 percent, or even more than 70 or 80 or 90 percent of the freezing side.
The chilling duct extends from a chilling inlet to a chilling outlet along the chilling side. The chilling duct may cover a large part of the freezing side, e.g. more than 50 percent, or more than 60 percent or even more than 70 or 80 or 90 percent of the chilling side.
The chilling duct may extend between the divider plate and a chilling duct inner wall which has a lower thermal conductivity than the divider plate. The chilling duct inner wall may e.g. be an isolated plate, e.g. an aluminium plate or plate of another material e.g. with a layer of an isolating material, e.g. a foam material such as a closed-cell extruded polystyrene foam, e.g. Styrofoam^™ or polyurethane foam.
In one embodiment, the heat transfer through the divider plate is at least twice the thermal convection through the chilling duct inner wall. The conductivity in Watt per meter Kelvin for the divider plate may e.g. be 2, 3, 4, 5 times that for the chilling duct inner wall, or even higher.
The device further comprises a chilling syphon plate which extends between the divider plate and the chilling duct inner wall. The chilling syphon plate is arranged such that it defines, in the chilling duct, two separate flow sections extending in opposite direction, i.e. a downwards flow in a downward flow section from the chilling inlet to a chilling siphon space and an upwards flow in an upward flow section from the chilling siphon space to the chilling outlet. The syphon plate could be identical to the divider plate, or it may have a higher or lower thermal conductivity than the divider plate. A lower thermal conductivity may reduce thermal conductivity when the flow in the duct is stopped.
The chilling syphon plate divides the chilling duct in two sections extending in opposite directions relative to gravity, i.e. the terms downward and upward refer to the orientation relative to gravity intended for the device. A car, truck, ship, and similar device has a specified orientation, and downwards and upwards refer to the orientation relative to the intended orientation of such devices. I.e. the mobile device may define one or more lower surfaces against which the mobile device is supported, and the chilling syphon space may be the lowest part of the chilling duct, i.e. that part of the chilling duct being closest to the lower surface.
The syphon plate may prevent a natural flow caused by gravity acting more on the heavy cooled air than on the warm, not yet cooled air.
The two sections may have the same cross sectional size and provide the same flow resistance, or they may have different cross sectional size and provide different flow resistance, e.g. such that the downward flow section is larger or smaller than the upward flow section.
The chilling outlet may be located between the siphon space and the chilling inlet when projected onto a vertical plane, i.e. the chilling outlet may, in a use situation, be located lower than the chilling inlet but higher than the siphon space. In that way, an increased flow resistance will typically be experienced in the upward flow section due to the mass of the air being cooled down.
The chilling duct inner wall, the divider plate, and the siphon plate may be parallel plates.
The device may further comprise a freezing syphon plate which extends between the divider plate and the freezing duct inner wall. The freezing syphon plate is arranged such that it defines, in the freezing duct, two separate flow sections extending in opposite directions, i.e. an upward flow in an upward flow section from the freezing inlet to a freezing siphon space and a downward flow in a downward flow section from the freezing siphon space to the freezing outlet. Herein, the terms downward and upward refer to the orientation relative to gravity intended for the device.
The mobile device may define one or more lower surfaces against which the mobile device is supported, and the freezing syphon space may be the highest part of the chilling duct, i.e. that part of the chilling duct being furthest away from the lower surface.
The two sections may have the same cross sectional size and provide the same flow resistance, or they may have different cross sectional size and provide different flow resistance, e.g. such that the downward section is larger than, or smaller than the upward flow section.
The freezing inlet could be arranged below the freezing outlet and the chilling inlet could be arranged above the chilling outlet. However, in one embodiment, the inlet and outlet are in the same vertical level and a divider structure is placed between the inlet and outlet to prevent air from flowing directly from the outlet and back to the inlet. The divider structure could be a plate extending into the chamber from a position between the inlet and outlet. The divider structure could be applied both in the chilling and in the freezing chamber when the inlet and outlet are close to the same vertical level or when they are in the same vertical level.
The freezing outlet may be located between the siphon space and the freezing inlet when projected onto a vertical plane, i.e. the freezing inlet may, in a use situation, be located lower than the freezing outlet. In that way, an increased flow resistance will typically be experienced in the downward flow section due to the reduced mass of the air which is heated.
The freezing duct inner wall, the divider plate, and the siphon plate may be parallel plates.
In a use situation, the divider plate may particularly extend in a vertical plane.
The device may comprise a chilling ventilator for creating a forced air flow in the chilling duct. In combination with the chilling siphon structure described above, the chilling ventilator may be used for allowing only convection depending on the operation of the ventilator.
The device may further comprise a freezing ventilator for creating a forced air flow in the freezing duct. In combination with the freezing siphon structure described above, the freezing ventilator may be used for allowing only convection depending on the operation of the ventilator, and without the siphon structure, the ventilator may be used for increasing the convection further by increasing the flow speed in the freezing duct.
The device may further comprise a ventilation control structure configured to control the flow speed in at least one of the freezing duct and chilling duct. The ventilation control structure being configured to control each ventilator individually. In that way, an increased control over the convection can be established, and particularly, the individual control may facilitate the cooling of several distinct chilling chambers by thermal energy from the same freezing chamber by controlling the flow speed in the ducts for each chilling chamber individually. The device may e.g. comprise one freezing chamber and two chilling chambers. Each of the two chilling chambers may comprise a ventilator which can be controlled individually, i.e. independent on the other ventilators, and the freezing chamber may comprise a ventilator which can be controlled independent on the other ventilators. The ventilators may e.g. be controlled based on a desired temperature for the chilling chambers, e.g. individually. In that way, the temperature can be set differently in each chilling chamber even though they are cooled by convection by the same freezing chamber.
In one mode, the ventilators are turned on or off upon reaching an initiating temperature limit or upon reaching a switch out temperature limit, the temperature being measured in the chilling chamber, in the freezing chamber, and/or in one of the freezing duct and chilling duct. In one embodiment, a ventilator for flow in the freezing duct is controlled based on the temperature in the freezing chamber or in the freezing duct, and a ventilator for flow in the chilling duct is controlled based on the temperature in the chilling chamber or in the chilling duct.
The freezing duct may extend between the divider plate and a freezing duct inner wall, and the freezing duct inner wall may extend between the divider plate and the eutectic cooling system. The eutectic cooling system could be located within the borders of the freezing duct inner wall in a projection onto a vertical plane.
The freezing duct inner wall may have a lower thermal conductivity than the divider plate. The plate may e.g. be an isolated metal plate, e.g. an aluminium plate, e.g. of the kind mentioned relative to the chilling duct inner wall.
The device may comprise one or more chilling shelfs for carrying items stored in the chilling chamber. It may be an advantage if all such chilling shelfs are located below the chilling inlet and optionally also below the chilling outlet.
The device may, likewise, comprise one or more freezing shelfs arranged for carrying items stored in the freezing chamber. It may be an advantage if at least one such freezing shelf is located below the freezing outlet. It may also be an advantage if at least one freezing shelf is above the freezing inlet. If the device has a freezing siphon structure, it may further be an advantage if at least one freezing shelf is located above the freezing outlet.
A defrost heater could be arranged to heat the chilling side, particularly arranged to heat the chilling duct to thereby remove ice in the duct.
The chilling duct may also comprise a drain opening in the bottom of the duct. The drain opening may be provided in the aforementioned siphon space. The drain opening may drain from the chilling duct into the remaining part of the chilling chamber or out of the chilling chamber. The opening may e.g. drain onto the external ground below the device.
A chilling drain structure may provide fluid communication from a bottom portion of the chilling siphon space.
Disclosed herein is also a method for refrigerating chilling chambers in a mobile cooling device according to independent claim 14.
The method may comprise the step of controlling the flow in each air flow duct individually, and the method may further comprise any step of using the structure of the mobile cooling device disclosed herein.

DETAILED DESCRIPTION OF EMBODIMENTS

In the following, embodiments of the invention will be disclosed in further details with reference to the drawing in which:

Fig. 1 illustrates a vehicle with separate chambers for freezing temperature and for chilling temperature
Fig. 2 illustrates schematically a separation wall for a mobile cooling device according to the invention;
Fig. 3 illustrates in further details an alternative embodiment of a separation wall for a mobile cooling device according to the invention, and
Figs. 4-5 illustrate an enlarged view of the separation wall.

The mobile cooling device 1 illustrated in Fig. 1 is a vehicle for distribution of frozen and cooled food products such as ice cream and cooled meat products. The vehicle has 5 separate chambers 2-6 with individual doors. For vehicles of this kind, and for containers and similar mobile devices, there is normally a well defined intended orientation relative to gravity, in this case defined inter alia by the wheels.
In the illustrated vehicle, the chambers 2, 3 and 4 are freezing chambers and chambers 5 and 6 are chilling chambers being cooled by thermal convection from the freezing chambers. Any other combination could be used, e.g. 2, 4, 6 being freezing chambers and 3 and 5 being chilling chambers.
Each of the freezing chambers 2, 3, 4 contains a eutectic cooling system. The eutectic cooling system comprises a eutectic element and a traditional evaporator of a compressor driven cooling system. The evaporator is typically embedded in the eutectic element.
The vehicle comprises a separation wall arranged between each of the freezing chambers and the adjacent cooling between the chilling chamber and the freezing chamber. In this case, the vehicle comprises a separation wall between freezing chambers and chilling chambers. Each of the separation walls has a structure illustrated schematically in Fig. 2.
Fig. 2 illustrates a wall 7 comprising a divider plate 8 having a freezing side 9 toward the freezing chamber and a chilling side 10 toward the chilling chamber. The divider plate 8 is affixed to the top or roof panel 11 and to the bottom or floor panel 12 of the vehicle such that all joining edges are sealed. Further, the divider plate forms a completely closed structure which prevents exchange of air between the freezing chamber and the chilling chamber. At the sidewalls (not shown), the divider plate is fixed and sealed to outer walls of the vehicle. Accordingly, the divider plate 8 completely separates the chilling chamber from the freezing chamber.
The separation wall further comprises a chilling duct inner wall 13 and a freezing duct inner wall 14. Between the chilling duct inner wall and the chilling side of the divider plate, the separation wall forms a chilling duct 15 facilitating a flow of warm air from the chilling chamber. The warm air is illustrated by the arrow 16. The warm air sinks downwards in the chilling duct when it is cooled by convection through the divider plate.
Between the freezing duct inner wall and the freezing side of the divider plate, the separation wall forms a freezing duct 17 facilitating a flow of cold air from the freezing chamber. The cold air expands and climbs in the freezing duct illustrated by the arrow 18 when it is heated up by convection through the divider plate.
The separation wall further comprises a chilling syphon plate 19 extending between the chilling duct inner wall 13 and the chilling side of the divider plate. The chilling syphon plate forms a downwards flow in a downward flow section 20 from the chilling inlet 21 to a chilling siphon space 22 and an upwards flow in an upward flow section 23 from the chilling siphon space 22 to the chilling outlet 24.
The chilling outlet 24 is located between the siphon space and the chilling inlet when projected onto a vertical plane.
In the embodiment disclosed in Fig. 2, the freezing duct only forms one section extending linearly between the freezing inlet 25 and the freezing outlet 26.
Figs. 3 and 4 illustrate a more advanced embodiment of the invention in which both the chilling duct and the freezing duct comprises a syphon plate.
In Fig. 3, the freezing chamber 27 is kept e.g. at minus 33 degrees Celsius by the eutectic system 28, and the chilling chamber 29 is kept e.g. at plus 5 degrees Celsius by heat transfer through the separation wall 30. The freezing chamber contains shelfs 31, 32 arranged above the freezing inlet 33 and at least one shelf 31 being arranged above the freezing outlet 34. The freezing outlet is fitted with an electrically driven ventilator 35.
The chilling chamber contains shelfs 36, 37 both arranged below both the chilling inlet 38 and the chilling outlet 39. In this way, the cooled air can pass the shelfs in the upwards section 40 of the chilling duct. A ventilator 41 is provided in the chilling inlet.
The separation wall 30 of the embodiment shown in Fig. 3 and 4 comprises a freezing syphon plate 42, and a chilling syphon plate 43
Fig. 4 illustrates an enlarged and simplified view of the separation wall in Fig. 3. The divider plate 46 is affixed to the top or roof panel 11 and to the bottom or floor panel 12 of the vehicle such that all joining edges are sealed. Further, the divider plate forms a completely closed structure which prevents exchange of air between the freezing chamber and the chilling chamber. At the sidewalls (not shown), the divider plate is fixed and sealed to outer walls of the vehicle. Accordingly, the divider plate 8 completely separates the chilling chamber 29 from the freezing chamber 27.
The freezing syphon plate 42 divides the freezing duct into a downward flow section A and an upward flow section B.
The upward flow section extends from the freezing inlet 33 to the freezing syphon space 44, and the downward flow section extends from the freezing syphon space 44 to the freezing outlet 34. In this embodiment, the freezing outlet is located between the siphon space and the freezing inlet when projected onto a vertical plane, and the freezing inlet 33 is arranged below the freezing outlet 34.
In the chilling chamber, the chilling inlet 38 is arranged above the chilling outlet 39. The chilling syphon plate 43 is arranged between the chilling duct inner wall 45 and the divider plate 46. The chilling syphon plate 43 divides the chilling duct into a downward flow section A and an upward flow section B. The downward flow section extends from the chilling inlet 38 to the chilling syphon space 49, and the upward flow section extends from the chilling syphon space 49 to the chilling outlet 39.
A drain opening 50 is provided in the chilling syphon space and allows water arising from de-icing to drain.
Fig. 5 illustrates further detail of the embodiment in Fig. 4, inter alia that the chilling inlet 38 and the freezing outlet 34 comprise electrically driven ventilators for creating a forced air flow in the chilling duct and in the freezing duct. Due to the combination between the syphon plates and the ventilators, the flow of air in the two ducts can be controlled precisely, and a natural flow when the ventilator is not operated, is prevented. Accordingly, the control of the ventilators may be used for controlling the thermal convection precisely. Each of the ventilators is controlled individually by a computer control system not illustrated. The control is based on a desired temperature in the chilling chamber, optionally further controlled on a desired temperature in the freezing chamber. Additionally, the ventilators can be controlled based on desired defrost.
The Freezing duct inner wall and the chilling duct inner wall are both isolated and therefore have lower thermal conductivity than the divider plate 45.
A defrost heater is build into the chilling syphon plate and enables fast heating and thus de-icing of the chilling duct.

Claims

A mobile cooling device (1) comprising a freezing chamber (2, 3, 4, 27), an eutectic cooling system arranged to cool the freezing chamber, a chilling chamber (5, 6, 29), and a separation wall (7, 30) between the chilling chamber and the freezing chamber, characterized in that the separation wall comprises a divider plate (8, 46) having a freezing side towards the freezing chamber, a chilling side towards the chilling chamber and forming a closed structure preventing exchange of air between the freezing chamber and the chilling chamber, the separation wall further comprising a freezing duct extending along the freezing side from a freezing inlet (25, 33) to a freezing outlet (26, 34) in the freezing chamber and a chilling duct extending along the chilling side from a chilling inlet (21, 38) to a chilling outlet (24, 39) in the chilling chamber, the chilling duct extending between the divider plate (8, 46) and a chilling duct inner wall (13, 45), a chilling syphon plate (19, 43) extending between the divider plate and the chilling duct inner wall and arranged to define a downwards flow in a downward flow section from the chilling inlet to a chilling siphon space and an upwards flow in an upward flow section from the chilling siphon space to the chilling outlet.
A mobile cooling device according to claim 1, the chilling duct inner wall having a lower thermal conductivity than the divider plate.
A mobile cooling device according to any of the preceding claims, wherein the chilling outlet is located between the siphon space and the chilling inlet when projected onto a vertical plane.
A mobile cooling device according to any of the preceding claims, wherein the freezing duct extends between the divider plate and a freezing duct inner wall.
A mobile cooling device according to claim 4, comprising a freezing syphon plate extending between the divider plate and the freezing duct inner wall and arranged to define an upwards flow in an upward flow section from the freezing inlet to a freezing siphon space and a downwards flow in a downwards flow section from the freezing siphon space to the freezing outlet.
A mobile cooling device according to claim 3, wherein the freezing outlet is located between the siphon space and the freezing inlet when projected onto a vertical plane.
A mobile cooling device according to any of the preceding claims, wherein the freezing inlet is arranged below the freezing outlet.
A mobile cooling device according to any of the preceding claims, wherein the freezing duct extends between the divider plate and a freezing duct inner wall, the freezing duct inner wall extending between the divider plate and the eutectic cooling system.
A mobile cooling device according to claim 8, wherein the freezing duct inner wall has a lower thermal conductivity than the divider plate.
A mobile cooling device according to any of the preceding claims, comprising at least one chilling shelf (36, 37) for carrying items stored in the chilling chamber, all chilling shelfs being located below the chilling inlet and below the chilling outlet.
A mobile cooling device according to any of the preceding claims, comprising at least one freezing shelf (31, 32) for carrying items stored in the freezing chamber and located below the freezing outlet.
A mobile cooling device according to any of the preceding claims, comprising at least one freezing shelf for carrying items stored in the freezing chamber and located above the freezing inlet.
A mobile cooling device according to any of the preceding claims, comprising at least one freezing shelf for carrying items stored in the freezing chamber and located above the freezing outlet.
A method for refrigerating chilling chambers (5, 6, 29) in a mobile cooling device comprising both a freezing chamber (2, 3, 4, 27) and a chilling chamber, wherein the freezing chamber is refrigerated by an eutectic cooling system and wherein the chilling chamber is refrigerated by the freezing chamber, the method comprising separating the chilling chamber from the freezing chamber by a separation wall (7, 30), the method being characterized by the separation wall (7, 30) comprising a divider plate (8, 46) having a freezing side towards the freezing chamber, a chilling side towards the chilling chamber and forming a closed structure preventing exchange of air between the freezing and the chilling chamber, and by providing a freezing duct and a chilling duct against opposite surfaces of the divider plate, the freezing duct extending along the freezing side from a freezing inlet (25, 33) to a freezing outlet (26, 34) in the freezing chamber and the chilling duct extending along the chilling side from a chilling inlet (21, 38) to a chilling outlet (24, 39) in the chilling chamber, the chilling duct extending between the divider plate (8, 46) and a chilling duct inner wall (13, 45), and by providing a chilling syphon plate (19, 43) extending between the divider plate and the chilling duct inner wall and by providing a downwards flow in a downward flow section from the chilling inlet to a chilling siphon space and an upwards flow in an upward flow section from the chilling siphon space to the chilling outlet.